1. Field of the Invention
The invention relates to a method of storing energy in an energy accumulator and of extracting energy out of it, and to a system for carrying out the method.
2. Description of the Prior Art
Due to the ever increasing utilization of energy and to the apparently forthcoming exhaustion of the high-grade energy sources available nowadays much work has been spent to reduce the immense waste of energy which is presently taking place and to devise new and improved methods and systems for the storage of energy.
A plurality of such schemes are discussed in a paper "Some Physical Chemical Aspects of Heat Storage" written by Martin Goldstein and appearing in "Proceedings of the United Nations Conference on New Sources of Energy", "Solar Energy, Wind Power and Geothermal Energy", Rome 21-31 August 1961, Volume 5, Solar Energy: II (United Nations, New York, 1964). In the section "Heats of Vaporization" (pages 413-416) Goldstein describes a system comprising two chambers, viz. a "hot chamber" and a "cool chamber", which contain a vaporizing liquid or substance having a lower vapor pressure at a given temperature in the "hot chamber" than in the "cool chamber". This substance may be present either as one component of a solution, the second component being relatively non-volatile, or else in a chemically bound form, such as hydrate or ammoniate. The cool chamber may condense the liquid directly, absorb it as a hydrate of lower stability, or absorb it in a solution from which it has a higher vapor pressure at a given temperature. The supply of heat to the storage chamber distills substance to the cool chamber where it condenses, losing heat to the environment. When as a result of a temperature drop on the hot side, the vapor pressure falls below the vapor pressure on the cool side, the substance distills back into the hot chamber, supplying heat as it condenses there. In a sense, the heat is stored in the atmosphere or environment, and removed therefrom when needed, through the medium of the volatile liquid.
As far as we know, Goldstein's scheme has not yet matured into any systems which are usable in practice. This is apparently due to the fact that Goldstein has found systems for carrying out his method to be very complex in construction and sensitive to changes in the environmental temperature. Furthermore, Goldstein has found it undesirable from an engineering point of view to maintain the system at pressures much lower than atmospheric, which is of great importance when the vaporizing and condensing substance or liquid is water. Last but not least Goldstein has not been able to find a sufficiently perfect substance.
A system based upon substantially the same principles and relating not to the storage of energy but to heating and cooling is disclosed in the U.S. Pat. No. 3,642,059 to Greiner.
The principal object of the present invention is to provide a useful, improved method in the storage of energy and a simple, inexpensive and reliable system for carrying out said method.